I work on the ATLAS
project experimentally measures subatomic particles taking data at the LHC
particle accelerator at CERN.

General
Information About ATLAS, LHC, and CERN

CERN (The European Laboratory for
Particle Physics) in Geneva, Switzerland is the world's largest particle
physics laboratory and is home to the Large Hadronic Collider (LHC).
The LHC is the largest particle accelerator
ever built (and for that matter the largest scientific instrument ever built).
If you are interested in learning about ATLAS and LHC take a look at the
ATLAS educational pages for students and the general public here.

The ATLAS project is fundamental research into subatomic particles and the nature of the universe.
The initial goal of the ATLAS experiment was to discover the long-sought Higgs boson predicted in a theory
first published in 1964. The theory used a technique known as "spontaneous symmetry breaking" to allow
particles to have non-zero masses in addition to predicting the existence of the Higgs boson.
The theory was first published in October of that year in 3 independent papers with
a total of six authors:

Robert Brout

Francois Englert

Peter Higgs

Gerald Guralnik

Carl Hagen

Thomas Kibble

On July 4, 2012 nearly 48 years later, the ATLAS experiment and its chief competitor the CMS experiment
announced independent, clear observation of the Higgs boson - the final missing piece of the theory
which had by then become so well verified and widely accepted that it became known as the
"Standard Model".

Here is a map of the LHC site of the CERN site showing how LHC fits into
the mountainous area around the CERN site near Geneva Switzerland:

This is how the LHC site looks from the air:

The ATLAS detector is buried underground and this is the building painted with a diagram of the detector is directly on the surface above the detector:

This drawing shows how the the ATLAS detector is installed 100 m underground:

Here is an drawing showing the parts of ATLAS:

This picture of a tall man looking tiny in the middle of the enormous ATLAS toroid magnet system to gives you an idea of the size of the detector:

Here is an event display of data recorded during LHC operation. The display shows what is very likely a Higgs boson decaying into 4 electrons via 2 intermediate Z bosons:

After sifting though trillions and trillions of proton collisions, ATLAS found a small bump at ~126 GeV/c in a mass plot for events where 2 energetic photons are observed:

And even the though the height of the mass peak is small, there is less than 1 chance in a million of the bump being a random fluctuation. There really is a Higgs boson: